SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '263a0794cf500299e026f9e2489588f828ed32af3a5aa70b62a6e78b554d9d0d' 
  AND token = 'fCcyGrqZFblSEtAMFuQqx8wkAazFn9kQStbvLCZvVCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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