SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '419bc700a143f11635329e8528aafc9557ea53f88aa077eac7cd4a361ff049a6' 
  AND token = 'V55m62TCmZ2eDUsmHjm4LGUxNkrHBJda27ExZZQfvn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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