SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b574282482df987142cf4167487dd361036f2471e4194d452fa5cd6274ae807c' 
  AND token = 'lYHABET2Msj9C/0ZNVJ3UB1VIyPSgJFRMEwtlvnMUZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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