SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd35b4c009a6f37458b92b207f6e289be8b44e5f6ce2a619cdc99ad6ec9dd5ac' 
  AND token = 'Q2op++SJGRdKVkOSPd0JxKyla5teiLiGwSECDYfMASQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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