SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d8b09d247dba55ab5f106e06a5409745134bdabdd658cf81caf546f3e3c2f4d' 
  AND token = 'HK/kYU5e7jXlnJzDQJZZiGbk8v5qk5ihW9Zc9IA81UQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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