SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c6c55caef74d2ae31cb6b12b29e1afcb06341471e2d85c9edb64717c1a1683f' 
  AND token = 'TcKMOYQawJWuMovsM9Yq8FuDG1ameKWWmXhP95ScXYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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