SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2e9068ca3f9fa01b1e845d0803d80687d142d7243285950e280b691d86f6d07c' 
  AND token = 'O8YQvH/ZGvpDfwfXf8owcmgNhQxQqYejIGe/Y5iAUrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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