SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3cf6c15f2c97b696b107be95300e832718da7fb5ada1344e252431bb2ec9fcc' 
  AND token = '/+hq2OR/hfuGwHdRwcL+8V29lHzG71CAUe61sJDCRyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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