SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '637bc68283dfcbd62751881172b6a6e666a6a0770ec581fea592c99c14521769' 
  AND token = '+ZkXSNj1ya9okd7B+6Xbg0FoVGwZZIAFCZ9o7hIuOxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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