SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '947c331fac969a853756ad543919e3ef001e5e5c13c7b0a796b18863aa53bcd4' 
  AND token = 'pCQa7jN/yUYU9YmQDXHIFIFsLlYaQWwZz2M5PJyXVC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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