SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9e95a2e77470369657dbd5897053506836688b2c3f0a244bbc5bd7a0267ca4c' 
  AND token = 'RntgNTmaNiNpgcWawfJ8dyLr0QPvkrZetZgvnOdeYgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}