SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf4836f3fbabd12172e0fac79903a68574eb8c7a5c744e716b081d6722cf5184' 
  AND token = 'QnDArtTBIKcQ1suRT1K+CXlVLUoqEcRZiOF+H+dnXyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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