SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e9776c2ea8494a8dfff9385e84f5787e1136792bb466a5b58acf3a381b65c14' 
  AND token = 'JL0fNQSRnasCmLrT2stq7rhfy6J4mQZAak46xccO5vA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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