SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1db265abf33a2bf6260bbcc5ba238647ba6b10a318b9f99966819b197e42bf7' 
  AND token = '9DHQSe4b6TKd6GirsQHQLrYvSdbIpLNBtfautqp/Q18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}