SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf1c74bfe57228cb0e0665b9ade853287d68dd21e48ca94bf38a27f15e168152' 
  AND token = 'xUpkcOHZ8YkvjSTB3IkRiSMkPRkwRojvizAhIbEpMIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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