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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7c8b80ef960b2b1f77f7690e20f62979c5c7f5471dba9ed88c4cfd74622fde7' 
  AND token = '1cQkuB1eEemU+RWQ+O3mzi3+klN9uuj0m0/wuL++Kwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}