SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '077b981de2fcabbcc61adaee8c57eba56942674ebbaceb4fbb5e07d58f5c9828' 
  AND token = 'UcqhZcCIvid5SzqdbjB4+n2YIAPZ5wQV5uGArye6DcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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