SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f90e4be5d43f6e7c6de7f03db1845f06f2616d0501f425448f7ec70de2515095' 
  AND token = 't9tAzr5UKISlNKhXqRYYb9fI7s7vJcR/GrbBbE60wzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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