SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '256be391408a6b5137aa831550eaabee5add13da7cb0fc185baee29d855fdb16' 
  AND token = 'JYoLw1vN/BRlYhXBgiS85SJVXPJvCzenqbUeB6QEtfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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