SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bbaa05b7b2c881990dbf09553e0abbeee85a101af9cbd1b1b7485e50e1d6d345' 
  AND token = 'k/+YTL5TOG6sSf5n8Ah4NEIF1R6kHwxGCp8BunNGWrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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