SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e11b1060251ac42c08600d53cf7856998ea7960d42f5d6bf3f1096c4eac2ac23' 
  AND token = 'kaENPxJp3Ey6C7VIG0001NNKft6sqSeAZday57epL7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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