SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68ac56f2bd7995f6b4f89f90c80838a2f12065106cd2e69dfe5b3535d092370b' 
  AND token = 'YzKDAhrKguoH0wIYCJtzpDZV9YvMnZl9HJ9Ice04tE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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