SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dd8276db935f47bdef219b0a8739cd8e2f16d294860c7d16bc8dbfca1546f05' 
  AND token = 'BDo+i22CkV3K4Wkr+CVhso/gRLz/+J5JQm2hv04W1oQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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