SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0c3779039697b2cb9df92154162269ec43d07556e224941720b926025dd72a3' 
  AND token = 'bqmWEBHLMJGe8BsEyYo4Y6R6FT5gKyokyUXHCVVqHDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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