SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '777510da97027f847a39a3d605cdd97279a39c7ad3bc5ac678168378fc30482a' 
  AND token = 'K/dpg+eCfv2b+1fOUmMn1MI6DngWF52j84fqYpkfPEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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