SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0a97ba50da0ba4990c5ba27e1524e91e769d6dc8a52ea0ce8a6506959445122' 
  AND token = '7wnGHl8DfTOD+ZSouw6KyijRcJOhkTgpxHWwgmpy6Ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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