SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23a9897eb4572ba4046464eb182b8fe23c39c40c1df848b6a97df53acff57437' 
  AND token = 'dYPVGUkbWdplNOG4iMwCHBrqyB0P+xV6CaXemJTpQEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}