SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baf5fb9183fdd28a9d8b6b9307d16b9c976a9b2ded6e6e535f47327007602ae6' 
  AND token = 'icJUVJdpfzbJGTBaHNmOj+f+8SC/3/+hw5WsQpMl/vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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