SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81a7eaf85ebe4143b4d48ce82dbb2c2516a437120f9faca394ec1ba03b9e9ecb' 
  AND token = 'Ju4P9uKJedly4onTgRNVIc87zO9zNfecAS+W+ityQx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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