SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3ec0e232c8eff3c0b19adb221523dbd3de0ae32b32046329bf47921ae48692b' 
  AND token = 'j9ZTMqnTgFduABCpVGFbAh+Af3NcnnsquoStDpuAPVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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