SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0e276d2afecbed93279b3b96977e9c7943a31541ea590ce15780ebeb5829be71' 
  AND token = 'UTs3BRIUDwlZRCA63OI21Q65ZjHCXjkNaJNbjLahj38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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