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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0678b22eb4a7cc49aa570b2d261b7b7ccc914e7a6de907c6cc8cd7ef428ca5c5' 
  AND token = '/0AWV/Jxb3q5Mof41EEcny8K/4mvMcHvMgi7ep6F2CI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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