SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f326a3e948e1bbbef12a40d7dac60ae334acd956d1e354f757d640a47048510f' 
  AND token = 'PjCdLxZjUveRFzLT/vOZJBI0AJFZ/cIlkn2NO9A12D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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