SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81e548c00dacdd5551b58666ff0957928da7133e53cb04378501f77fe21c116b' 
  AND token = '5RlGZxJv/GAggVylNruLl2PfDvRD0oY9Xd6vdXWH+Ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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