SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84744b09f7af3a4239eccb3017dba9a50a26a71d25ac7166937a687dc8c08fe4' 
  AND token = 'G+RrZKBXdcJUHDpfywk/ahVSSCGdfPOEr2bpGx5clQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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