SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7c44cc4638765f5999d2d5bfce01d766c560a29e43129debced3cc08a69983f' 
  AND token = '8hMF1FXT7yl3cfuTZXdKLi8uPhgljAtcwVNTGTC2Brg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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