SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75f859ac11f0564d23af34cc8b644abfd41e4ea2eff33214bc50710065831b4a' 
  AND token = 'ptpDzqB2dVTSpvMG6zXViRtTPZXnCO3JTLGGD+AD7Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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