SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3e4271c816ee2690438a4e219d513fa4bc4f478203e09e398c7ac80fab0ab7a0' 
  AND token = 'VCuXgou493tQuTF3fBFrDEWLzNMKj/6/hekGeIpoK3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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