SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e018ac1e243b816007abccbd0459eeb0411c066e9a1f682f5d983709df338b29' 
  AND token = 'LOKD80orx0UwAmRoCoEb60KhVcAtRthLveFjcXCKhRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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