SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b918cc5397466628d9bc71c9c08b5725295a8f1f0332655df35bc7bcd733f35d' 
  AND token = 'aZpXBJ9dd1HVZp5mPVGK6CH47RCGPtxMxQqZCqn1vig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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