SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07a27c16d8205ece323baf5d082be8cb604c2cb00872021b9f8489c906c69342' 
  AND token = '2l/NgvCpJU+qCoW3GhSSeeATG6tRnjwgFZGwd/lXvRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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