SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14e83c28688862ed6dddf58aeac0807e1f760bafb7df98e17a558a850be97cf4' 
  AND token = 'lkW3yaLNYMRZAkETgCRS+ZvnQcZn704HBpKE6Vl60uc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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