SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '112338836c81a64436e483376ddbe7a6468a5959b0e25607ec80633de2beaccc' 
  AND token = 'e/Dx88ZJcFGkoS07AjIIzVRyUzVdXGaLOpWWYx9pMls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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