SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c6663a219865ed4c2504542af064e8fede39940d2b21dd51e2adbc88411cf9a' 
  AND token = 'qp2z7UskCOBNPtJt/bWhVcQQsfGmnFi+lBzUUROhBms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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