SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bbd157d9c7974773cd2c404074694b8df31c3bfdc04693ce7991e20b0691003e' 
  AND token = 'vDauSGAMIpfNNB5jcdGur3TI6MSxRtyFjgQD/JqOpPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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