SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6d1fc4860514943d96324c066fe70a5ae074e69f727f4731b0b24bb80c4f30d' 
  AND token = 'VRLGvvwU/W+n4YnxreEVhrIguU13UtH+jOamWvMLUPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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