SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0ed101d787a176177c24d8f9b09cd1caf748ee8735c95403309ffd1f2e7fc7e1' 
  AND token = 'b+O11dfCo3SROf80uvCh9XOE3hhgnUryhD8melLqPQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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