SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6742698a894a96749573afbe93e7c0c32396d8fa30d6be02a3d5ff0b86c8bf4d' 
  AND token = 'XXB8G2mEYMuI80zRBFrcpQV9ipXMBJQ2j7oToZYCLsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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