SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd845e9639c817cad06c13c505bec7e4c29673af3f9521c762b1aeb932c8976d4' 
  AND token = 'Q7tSnNk6BxCmzKlZlHtPF0vGFBWDMrp3xpeTtVXvn2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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