SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a90f2628c172838dc1ba423a8d760b6098358ab02fc1bcf4f68cef9ea9ab5e2d' 
  AND token = 'AkJ9KGqZlxQ8TY/MtB5Xz2sx0HprZQfnpGTGjcJZCv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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