SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5450239684f2eb5db25bbdc28ae6f9805116eb63b36854ecf29000b4d4681c7' 
  AND token = 'EiyZjMBN3h08qI6Z+/PQxrDJxCuG/xDFUxBTaZUP1Wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}