SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1411f19631ea49247a278264d6c0d724b68e486db576942c091b8282279eeda' 
  AND token = 'h5H6onsSBdutKn1qielk7d5boRfjEZj0fuxii1XppZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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