SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54cd71ec9f5c1af2068e3176a0e6b3b9c6308766555137e75b3a345466bd3fb2' 
  AND token = 'ZtIlj8XLl7g7qzfQFy1hpGV4Mnr1jKYYOe7gs8z+dZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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