SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a237373db242ecfaf1c4f6568eeb1801c4b3c5fc142d44aa32e3c32a4890ac31' 
  AND token = 'l4uGXQooMCLRCr9vQxpRoleQsS13HCssZSwSSKsRiBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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