SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c308240bbac385bcb9a5ac8b73cd2deae29d602c20804aaf408a48deb25930' 
  AND token = 'tVRkqBiUP+5qojJGKxK2tsoF2n6MhZpv1Gk9j7IYuXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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