SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0538f4559927f80022e09be4040612afe843c89d861af27d1c198f943f782032' 
  AND token = 'R6u2IrPDmdq0+NgXxphl9xciStxw+70bdOW9oAoOUBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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