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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4ad8df09c41a7368d7ac78843329211eab3215cf9fb78d1dfacd67437674ea' 
  AND token = 'MzNZXMWG8dHSYt7Ag/Fc78Uwt5ZlQv/GfSZZzaRLXVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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