SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc4143d320ca4f4172271d09d36fdc12e202a0287c94e30c85aa0a0482be0c25' 
  AND token = 'TM/mtpstzCkBEBKUEi7D8au1wXZKVHl71s+gXunAN3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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