SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f28ab006259151fa08b4f3cc6bc0f5aa6d512cb0eb1b1cb9bd84aee5e9a6aca0' 
  AND token = 'pVfACYXKaxp9npmhUrLu7PcCNOOxRLWi4IF2U5c+ya4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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