SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36db091ab423f1d0fe06dab1c7f9db98d4c55c392832fecc2fd0f3714f0a6b6d' 
  AND token = '5YH6OkmLwDZB/BQeQGQC2FlcKN/OzcWcqVnmL6ldwNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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