SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3443591945654dc28354009cbb2e500a82d30effff07527e47235abdd007fbd9' 
  AND token = 'XOiPY1iKczOolIEZjqxtacNpuj7yEaHBmT3UYNuqsvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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