SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8af3fd10ab3d586781698a6742d34a364799d71e229753e7ceeef20213432f1' 
  AND token = 'Anpr1ACp3Q7StWY7XfCcI1ZqaY09NwI3OfLOMXYwYBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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