SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c78cba4aef5717946a671055188711384cb050773deb927ab7d875b01f3bca53' 
  AND token = 'BlMO0oVxmyWlHyqzRsXxCdpHISU0g6iRIlmDRfLs57M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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