SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1a050ee20ec720eac34d6c6724594b86ab5d462cd55fbed4a1288e623b0c8137' 
  AND token = 'epYCxSgoEmi2pCucrzFmUWcgxTdBeS6CsmqIPKmVjHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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