SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4f9dc683deab47fa21216b054ed36395c549ad893d27237ca6393ea5660df92' 
  AND token = 'CRLJVkilp7PZveOoqhwjPS8YkcYm14QHlitXBUuIuhw=' 
  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"
    }
  }
}