SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '634517afbee9bfb49c354202d74491985830a94aa0bf0edb41ec3ffd0b1c1537' 
  AND token = 'Fl8sYPseNF1ZaK+2GZUIaO5U38v6SRXxbANBN2jUQ3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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