SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84c00507c8aad484db834997e31306269d92005baf06ee7cfef6b6fb61935d97' 
  AND token = '5FpXrQThzGU+I6q+j8eDYfVYqQIHQrNOhnXlnqEG5IU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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