SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38a4b16413672700f95b70c9b0bf467894c6ea441b965105b8da3b66415114bb' 
  AND token = '4aUYNcOnxR6cbC8vmPuoTaVsZUPEFmTQhM3UtTVuAmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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